AB0356 THERAPEUTIC DRUG MONITORING: STANDARDIZATION OF PROMONITOR QUICK IFX AND PROMONITOR QUICK ADL POINT OF CARE TESTS WITH WHO INTERNATIONAL STANDARDS FOR THE QUANTIFICATION OF INFLIXIMAB AND ADALIMUMAB IN WHOLE BLOOD AND SERUM
Authors: A. Ametzazurra, J. Pascual, L. Del Rio, A. Urigoitia, D. Nagore, M. B. Ruiz-Argüello
Journal: Annals of the Rheumatic Diseases (2022)

Background Promonitor Quick IFX and Promonitor Quick ADL are rapid point of care lateral flow tests (LFT) based on a sandwich immunoassay for the quantification of infliximab (IFX) and adalimumab (ADL), respectively, in human whole blood (finger prick or venous) or serum. These tests are to be used as an aid in Therapeutic Drug Monitoring (TDM) of rheumatic and inflammatory bowel disease patients under anti-TNFα therapy. The international standards (IS) developed by World Health Organization (WHO) for IFX and ADL allow harmonization and comparability among different assays. Objectives The aim of this study, was to show that Promonitor Quick IFX and Promonitor Quick ADL can measure either reference or biosimilar drugs, as well as to evaluate the agreement of Promonitor Quick IFX and Promonitor Quick ADL tests and the WHO IS. Methods Clinical and Laboratory Standards Institute EP10-A3 guidelines were followed to estimate the bias of Promonitor Quick assays when used to quantify IFX or ADL in samples containing the reference drugs, biosimilars or the WHO IS. Briefly, whole blood was spiked with four known concentrations of IFX or ADL, including current clinical decision levels. Ten replicates were measured of each level along two days. Promonitor Quick IFX was evaluated using the reference drug, SB2 and CT-P13 biosimilars, and the WHO IS (NIBSC 16/170). Promonitor Quick ADL was evaluated using the reference drug, ABP501 and SB5 biosimilars, and the WHO IS (NIBSC 17/236). Results were obtained in combination with the automated portable reader PQreader. Results Bias was estimated by comparing the observed concentration of drug spiked whole blood samples. Each biosimilar was compared to the reference at the different drug levels tested. Results showed that Promonitor Quick IFX and Promonitor Quick ADL are able to measure equivalently any molecule (see Table 1). Table 1. Promonitor Quick IFX bias results in whole blood samples. Each molecule was compared to the reference drug. IFX concentration (μg/mL) Bias (%) CT-P13 SB2 GP1111 WHO IS 3 14% 3% 4% 8% 7 9% 0% 5% 15% 10 1% 5% 6% 8% Promonitor Quick ADL bias results in whole blood samples. Each molecule was compared to the reference drug. ADL concentration (μg/mL ) Bias (% ) ABP501 SB5 WHO IS 3 17% 2% 3% 5 13% 3% 12% 8 2% 2% 7% 10 5 17% 2% Similar results were obtained when serum matrix was used. The accuracy or closeness of the agreement between the result provided by Promonitor Quick IFX and Promonitor Quick ADL and the true value of the measurand was assessed by measuring the IS developed by the WHO (see Table 1). Conclusion Promonitor Quick IFX and Promonitor Quick ADL allow monitoring of patients treated with IFX and ADL, respectively, with just a finger prick sample. Both tests can quantify reference and biosimilar drugs with equivalent results. Moreover, comparable results were obtained with the WHO IS, and thus, demonstrate that Promonitor Quick tests are suited to accurately determine drug levels at the clinical decision points in both whole blood and serum, proving to be an effective and valuable tool in TDM and immediate decision making in the doctor office or hospitals. Disclosure of Interests Amagoia Ametzazurra Employee of: Employee of Progenika Biopharma - Grifols, Javier Pascual Employee of: Employee of Progenika Biopharma - Grifols, Lorena Del Rio Employee of: Employee of Progenika Biopharma - Grifols, Ane Urigoitia Employee of: Employee of Progenika Biopharma - Grifols, Daniel Nagore Employee of: Employee of Progenika Biopharma - Grifols, M. Begoña Ruiz-Argüello Employee of: Employee of Progenika Biopharma - Grifols